JIT Image Manipulation

A simple way to manipulate images "just in time" via the URL. Supports caching, image quality settings and loading of offsite images.

• Version: 1.16
• Date: 16th September 2012
• Requirements: Symphony 2.3 or later
• Author: Alistair Kearney, [email protected]
• GitHub Repository: http://github.com/symphonycms/jit_image_manipulation

Installation

Information about installing and updating extensions can be found in the Symphony documentation.

Updating

Since version 1.15, JIT configuration has moved from /manifest/ to the /workspace/ folder. This change will automatically happen when you update the extension from the "System > Extensions" page.

Due to some .htaccess changes in Symphony 2.0.6+, it is recommended that you edit your core Symphony .htaccess to remove anything before 'extensions/' in the JIT rewrite. It should look like the following regardless of where you installed Symphony:

### IMAGE RULES
RewriteRule ^image\/(.+\.(jpg|gif|jpeg|png|bmp))$ extensions/jit_image_manipulation/lib/image.php?param=$1 [L,NC]

It is not absolutely necessary to do this, but may prevent problems with future releases.

Usage

Basics

The image manipulation is controlled via the URL, eg.:

<img src="{$root}/image/2/80/80/5{image/@path}/{image/filename}" />

The extension accepts four numeric settings for the manipulation:

1. mode
2. width
3. height
4. reference position (for cropping only)
5. background color (for cropping only)

There are four possible modes:

• 0 none
• 1 resize
• 2 resize and crop (used in the example)
• 3 crop
• 4 resize to fit

If you're using mode 2 or 3 for image cropping you need to specify the reference position:

+---+---+---+
| 1 | 2 | 3 |
+---+---+---+
| 4 | 5 | 6 |
+---+---+---+
| 7 | 8 | 9 |
+---+---+---+

If you're using mode 2 or 3 for image cropping, there is an optional fifth background color setting. This can accept shorthand or full hex colors.

• For .jpg images, it is advised to use this if the crop size is larger than the original, otherwise the extra canvas will be black.
• For transparent .png or .gif images, supplying the background color will fill the image. This is why the setting is optional

The extra fifth setting makes the URL look like this:

<img src="{$root}/image/2/80/80/5/fff/{image/@path}/{image/filename}" />

• If you wish to crop and maintain the aspect ratio of an image but only have one fixed dimension (that is, width or height), simply set the other dimension to 0

Trusted Sites

In order pull images from external sources, you must set up a white-list of trusted sites. To do this, go to "System > Preferences" and add rules to the "JIT Image Manipulation" rules textarea. To match anything use a single asterisk (*).

Recipes

Recipes are named rules for the JIT settings which help improve security and are more convenient. They can be edited on the preferences page in the JIT section and are saved in /workspace/jit-image-manipulation/recipes.php. A recipe URL might look like:

<img src="{$root}/image/thumbnail{image/@path}/{image/filename}" />

When JIT parses a URL like this, it will check the recipes file for a recipe with a handle of thumbnail and apply it's rules. You can completely disable dynamic JIT rules and choose to use recipes only which will prevent a malicious user from hammering your server with large or multiple JIT requests.

Recipes can be copied between installations and changes will be reflected by every image using this recipe.